[RFC PATCH 7/5] xfs: add block device provisioning for fallocate

Dave Chinner
2023-10-08T23:45:25Z

From: Dave Chinner <dchinner@redhat.com>

Provision space in the block device for preallocated file space when
userspace asks for it. Make sure to do this outside of transaction
context so it can fail without causing a filesystem shutdown.

XXX: async provisioning submission/completion interface would be
really useful here....

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_bmap_util.c | 42 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 37 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index fcefab687285..5dddd1e7bc47 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -772,6 +772,37 @@ xfs_free_eofblocks(
return error;
}

+static int
+xfs_bmap_provision_blocks(
+ struct xfs_inode *ip,
+ struct xfs_bmbt_irec *imap,
+ int nimaps)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_buftarg *target;
+ int i;
+
+ if (!xfs_is_provisioning_blocks(mp))
+ return 0;
+
+ target = xfs_inode_buftarg(ip);
+ if (!target->bt_needs_provisioning)
+ return 0;
+
+ for (i = 0; i < nimaps; i++) {
+ int error;
+
+ error = blkdev_issue_provision(target->bt_bdev,
+ XFS_FSB_TO_DADDR(mp, imap->br_startblock),
+ XFS_FSB_TO_BB(mp, imap->br_blockcount),
+ GFP_KERNEL, 0);
+ ASSERT(error != -EOPNOTSUPP);
+ if (error)
+ return error;
+ }
+ return 0;
+}
+
int
xfs_alloc_file_space(
struct xfs_inode *ip,
@@ -780,7 +811,6 @@ xfs_alloc_file_space(
{
xfs_mount_t *mp = ip->i_mount;
xfs_off_t count;
- xfs_filblks_t allocated_fsb;
xfs_filblks_t allocatesize_fsb;
xfs_extlen_t extsz, temp;
xfs_fileoff_t startoffset_fsb;
@@ -884,15 +914,17 @@ xfs_alloc_file_space(
if (error)
break;

- allocated_fsb = imapp->br_blockcount;
-
if (nimaps == 0) {
error = -ENOSPC;
break;
}

- startoffset_fsb += allocated_fsb;
- allocatesize_fsb -= allocated_fsb;
+ error = xfs_bmap_provision_blocks(ip, imapp, nimaps);
+ if (error)
+ break;
+
+ startoffset_fsb += imapp->br_blockcount;
+ allocatesize_fsb -= imapp->br_blockcount;
}

return error;